Lithium ion batteries are being used in a variety of commercial products ranging from hand-held devices to automobiles. Advantages associated with lithium ion batteries include their high energy density and their ability to be recharged. Unfortunately, there are also several disadvantages associated with lithium ion batteries. For example and in general, lithium ion batteries tend to exhibit low power density due to the speed of lithium ion diffusion on the batteries' electrodes. More specifically, cathode materials in many commercial lithium ion batteries have a specific capacity (or discharge capacity as it is also known) in the range of 120-200 milliamp hour per gram (mAh/g), whereas the usual anode material of graphite has a practical specific capacity of approximately 350 mAh/g. Increasing the specific capacity of a battery's anode would improve battery performance.
More recently, it has been proposed to make lithium ion battery electrodes from a layered arrangement of a carbon nanotube sheet and a copper foil. However, typical thicknesses of a copper foil (e.g., on the order of 25-100 microns) adds considerable weight to the battery.